Distance running is a great past-time, but a potentially dangerous one. There has been a huge rise recently in the popularity of marathon and half-marathon training, and for good reason. It's a very fun and easily acquired skill. Practically anyone can do it. It doesn't take the grace and speed of a great basketball player, or the precision and focus of a baseball star. All it takes is your own motivation and drive.
The great thing about running is that you are only competing against yourself. You don't have to worry about someone who is so much better than you that he is going to make you look bad. You only work against yourself and challenge yourself.
Another great thing about distance running is that you can only get better. Everyone gets better if they consistently practice. Even if you are just shaving off a few seconds from your splits, you are improving. A split is a predetermined distance; for example if you are running 5 miles, a split would be something like a half or a quarter of a mile. Basically it is a set distance so that you can determine how fast you are running.
However, running does come with some dangers. Some runners try to do too much too soon. Some try to recover from an injury or illness too quickly, and push their bodies too hard. You can easily twist an ankle, hurt your IT band or pull a muscle.
The IT band injury is the most common, especially for people new to distance running. The IT band is a tendon and muscle that runs up the side of your leg from your knee to your hip. Often, running only on one side of the track or street will put extra tension on one IT band, and this will lead to injury. Try to switch the direction that you run in to help prevent this.
Stretching is a crucial component to preventing soreness after a long run, or to simply keep you from getting injured. You should stretch your calves, quadriceps, hamstrings, gluts, and your IT band. You also want to stretch your neck and back as runners tend to hold a lot of tension in these areas.
Another important tool for avoiding injury while running is to buy good shoes. If you are serious about distance running you are going to be doing a lot of it. Think about the hundreds of miles that your shoes will suffer through, and how much impact your shoes absorb for your feet and body. If your shoes are old and worn, they can't protect you. Go to a reputable shoe store and have someone fit you with proper running shoes.